1. Field of the Invention
This invention relates to an orthodontic appliance including a low pull and/or a high pull, which low pull preferably extends through and is slidable in a guide sleeve of a nape pad, and the low pull and/or the high pull are provided at each end with a series of holes for a selective connection to spring elements connected to bow means.
2. Description of the Prior Art
German Patent Specification No. 26 23 943 discloses such an orthodontic appliance comprising an extra-oral or outer face bow and a low pull for transmitting spring forces to an oral or inner correcting bow which is connected to molar teeth to be corrected. Spring elements are provided on both sides in the outer bow and in use extend beside and approximately parallel to the inner terminal portions of the inner bow and the spring elements are succeeded by the hooklike means for connection to the low pull, which extends through a guide sleeve and is in contact with a slideway in said sleeve. The low pull bears on a pad, which bears on the nape. The spring elements provided on both sides consist of tension springs and cooperate with scale-bearing housings so as to provide spring scales. A further development of that appliance is disclosed in the specification of German Pat. No. 26 48 989, which is a patent of addition to German Pat. No. 26 23 943.
In accordance with U.S. Pat. No. 4,353,691 a telescopically extensible hook connector for such orthodontic appliances includes a rubber cord for exerting a tensile force.
In the known orthodontic appliances the telescopic pulling means are inconvenient for the patient and are bulky, conspicuous and also expensive.